The invention relates to mounting composite material blades on a disk of a rotor wheel of a gas turbine engine.
The intended field is that of aeroengines and of industrial turbines.
A rotor wheel of a gas turbine engine, e.g. such as a low pressure turbine wheel of an aeroengine, generally comprises a disk having a plurality of slots at its periphery, each slot having a blade of the wheel mounted therein via its respective root.
It is becoming common practice to replace metal blades for such a rotor wheel with blades that are made out of composite material, with the rotor disks continuing to be made out of metal. The use of a composite material for fabricating blades is justified by very good ability at withstanding the high temperatures to which the blades are subjected. Reference may be made for example to patent application FR 2 939 129 filed jointly in the names of Snecma and Snecma Propulsion Solide, which application describes the fabrication of a turbine engine blade by making a fiber preform by three-dimensional weaving and densifying the preform with a matrix.
Compared with a metal blade obtained by casting, a composite material blade presents certain drawbacks, in particular associated with mounting it on a metal disk. In particular, a method of the kind described in document FR 2 939 129 does not make it possible to obtain blades with dimensional tolerances that are as fine and as accurate as can be obtained with metal blades. This results in large amounts of functional clearance between the blade roots and the slots of the disks in which they are mounted. Unfortunately, such clearance leads to the blades tilting about their roots, thereby reducing the performance of the engine (gas leakage between the blade platforms is increased).